Hepatitis C (HCV) is a cause of viral infections. There is as yet no adequate treatment for HCV infection but it is believed that inhibition of its RNA polymerase in mammals, particularly humans, would be of benefit.
Published International patent application WO 93/00334 (Fidia-Georgetown Institute for the Neurosciences) discloses the following indole derivatives:
where A, Z, R1, R2, R3, R4 and n are defined therein, as useful in compositions and methods for treating psychiatric and neurological disorders. However, this document does not disclose the use of tetracyclic indole derivatives in treating or preventing viral infections.
Published International patent application WO 2005/080399 (Japan Tobacco Inc.) discloses the following fused heterotetracyclic compounds:
where A, X, Cy, G1, G2, G3, G4, G5, G6, R1, R2, R3, R4, R5, R6 and a are defined therein, and their use as HCV polymerase inhibitors.
Published International patent application WO 2006/020082 (Bristol-Myers Squibb Company) discloses the following fused tetracyclic compounds:
where A, B, R1, R2, R3 and n are defined therein, and their use in treating hepatitis C.
Published International applications WO2006/046030 and WO2006/046039 (both Istituto Di Ricerche Di Biologia Molecolare P. Angeletti SpA) disclose certain tetracyclic indole derivatives:
wherein R1, R2, A, Ar, W, X, Y, and Z are defined therein, useful for the treatment or prevention of infection by hepatitis C virus.